Urinary tract infections (UTIs) are responsible for an estimated 10 million outpatient visits and more than one million hospitalizations each year in the United States. Annual health care costs attributable to UTIs exceed one billion dollars. Approximately 50% of women will have at least one UTI during their lives, and many of these women experience recurrent UTI.
Uropathogenic Eschericia coli (UPEC), by far the most common uropathogen, is the causal agent in greater than 85% of uncomplicated UTIs. The organisms are also known to cause hospital acquired infections associated with injury, surgical procedures, or catheterization. UPEC present a complex ecological case among the pathogenic E. coli. UPEC can colonize the human intestinal tract without causing disease, yet they can sequentially colonize the perineum, urethra, bladder and kidney. Known E. coli virulence factors that contribute to UTIs are fimbriae (e.g. type 1 fimbriae and Pap fimbriae), iron acquisition systems, hemolysin, cytotoxic necrotizing factor-1, and the Sat autotransporter. Environmental cues used by UPEC for expression of genes needed for colonization of the bladder and kidney have not been described in the literature.
Urinary tract infections in humans are generally treated with antibiotic therapy. Treatment of UTIs may be complicated by strains that are resistant to antibiotics, particularly to those antibiotics in common use. The identification of new UPEC-specified pathogenicity factors will facilitate the development of new methods of treating or preventing UTIs.